If you are playing on local (South African) servers, then a 384, 512 or 4MB ADSL line will be fine, giving you latencies under 50ms on just about all products offered by ISP's.
If you're playing on international servers, you're going to have to test each product individually to see if it can meet your game's requirements.

An expensive exercise.

And, once you have found the product that works, expect it to no longer work in about 3 weeks time.

At what times do you access the internet? Most "shaped" accounts are only really shaped during the day. You generally get good latencies at night. I have an Afrihost "semi-shaped" account and the delay i have online in HoN is barely noticeable and even less so if I play on one of the SA servers. DON'T PLAY FPS ON INTERNATIONAL SERVERS, YOU WILL FAIL! Stick to the local servers for most of your FPS stuff and you can safely play RTS, i.e. starcraft2, supcom, CoH, ect on int servers without much delay.